Mast Cell Tumor - Getting it right! By Shelley Newman DVM
There is no correlate to this common canine cutaneous tumor type in humans. And over the years of my research, many different angles have been taken to try to understand, treat and prognosticate it better.
Initially, certain breeds seemed predisposed; Boxer, Boston Terrier, Weimaraner, and that is still the case, suggesting a familial or genetic susceptibility.
Later, genetic mutations in the c-kit gene were determined to be involved in a proportion of the cases.
The c-kit receptor was then used as a molecular target to confirm the origin of round cell tumors, as being of mast cell origin and later as a prognostic indicator.
The vast majority of diagnoses and treatment were based on surgical excision. Since our research almost 20 years ago, the accepted surgical excision size is 3 cm lateral to the grossly visible mass and one facial plane deep has continued to be the gold standard.
In some rare instances, incompletely resected tumors, failed to come back and completely resected relatively quiescent variants returned with a vengeance. This type of behavior makes pathologists concerned that they not read the microscopic signals inappropriately.
Molecular techniques and antibody-targeted stains have been explored to try to get a better handle on behavior of these tumors, in the case the naked eye of the pathologist is not good enough to distinguish these.
Lastly, not all mast cell tumors are cutaneous, they can occur in dogs in the gastrointestinal tract and in the spleen of cats. But there were also variants deeper in the skin of dogs that were not completely characterized in the original grading system produced by my colleague at the Animal Medical Center, Dr. Amiya Patnaik. Canine cutaneous mast cell tumor: morphologic grading and survival time in 83 dogs - PubMed (nih.gov)
Subsequently, I characterized the largest collection of subcutaneous mast cell tumors, that suggested that even based on location of origin within the skin, the prognosis was affected.
So, does this all help to explain the elusive nature and multi-factorial aspects of canine cutaneous mast cell tumor?
Blog written by Shelley Newman, Veterinary Pathologist
ABSTRACT IMAGE OF A MAST CELL TUMOR